We plan to measure production and secretion rates of androgens and estrogens using the specific activities in blood following infusions of radio-labeled androgens and estrogens. These measurements will be done in pre- and post-menopausal women of varying age to determine the ovarian function in these groups of subjects and to determine the importance of peripheral tissues in the inter-conversions of androgens and estrogens and the aromatization of androgens. Measurements will be made of androgens and estrogens in peripheral, arterial and ovarian vein blood to determine the ovarian secretion of these steroids in post-menopausal women undergoing oophorectomy and/or hysterectomy. By these methods we will assess ovarian function and the effect of age and menopausal status on this function.